A Method for Reducing Residual Stress of Laser Cladding Metal Coating

Abstract

The invention discloses a method for reducing the residual stress of laser cladding metal coatings. Before cladding, the invention prefabricates regularly arranged groove microstructures on the substrate, and the laser focus falls on the center of two adjacent grooves. , the melting channel and the groove are parallel to each other. The invention is suitable for laser cladding technology, and is characterized in that the residual stress of formed parts is low, effectively avoids cracks, cracks, warping and deformation phenomena, does not require additional equipment, and is easy to operate.

Description

Technical field[0001]The invention relates to the field of laser processing, in particular to a method for reducing the residual stress of a laser cladding metal coating.Background technique[0002]Laser cladding is a method of using high-energy laser beams to cladding metal powder on a substrate to prepare a metal coating. This method has the advantages of high bonding strength with the substrate, low dilution rate, high hardness, wear resistance and corrosion resistance. . In recent years, surface modification and strengthening of key metal parts based on this technology has become a research hotspot and has shown broad application prospects. However, due to the uneven distribution of laser energy, the large temperature gradient during the cladding process, and the large solidification rate, the laser cladding cermet layer will cause cracks and other defects due to residual stress, and the cladding layer is easy to crack, which seriously restricts In order to promote its further pro...

AI Technical Summary

Problems solved by technology

[0004] First, optimize the process parameters from the aspects of laser power, spot diameter, scanning speed, overlapping rate, scanning strategy, etc., and change the stress distribution inside the part to reduce the residual stress, but the mechanical properties of the part cannot be taken into account;

[0005] Second, add a preheating module on the shaped substrate, heat the bottom of the substrate before the laser scans the substrate, reduce the temperature gradient between the formed part and the substrate, thereby reducing the residual stress caused by the excessive temperature gradient , but preheating the substrate will increase the complexity of the equipment and the difficulty of control;

[0006] Thirdly, post-treatments such as hot isostatic pressing and stress relief annealing are carried out on the formed parts to eliminate the residual stress inside the formed parts. Although the residual stress can be reduced to a certain extent, the parts will still be deformed and cracked after processing to the preventive effect;

[0007] Fourth, oxides such as MgO, CeO2, Y2O3 are added during the cladding process to reduce residual stress, but the addition of oxides makes the process complicated, the production efficiency low, and the processing cost high

[0008] In summary, in the prior art, there is a lack of a simple and low-cost method that can effectively reduce residual stress and avoid cracking of the molten metal layer

Images